Hymns and Gregorian Chant

Gospels are notated in the Tonus Evangélii, Tonus Antíquior and Tonus Ad Líbitum; Lessons, Orations, and Blessings are notated in the Tonus Feriális
cenacle.co.uk/products.asp?category=Tradition&subcategory=Hymnsand

I suggest before singing the tonus solemnior that perhaps you could start with the tone for the tonus solemnis , which people are more likely to know
wdtprs.com log/2011/06/prayercaztpodcazt-pentecost-the-whole-nine-yards

Beethoven: Missa Solemnis – review, Music, The Guardian

For a conductor often associated with slowish speeds, this idiosyncratic Missa Solemnis is surprisingly uptempo and volatile, writes Tim Ashley
www.guardian.co.uk/music/2012/apr/12 eethoven-missa-solemnis-lpo-review

New Liturgical Movement: December 2007

straightforward and allow for options. Surprisingly, there are no rubrics concerning the three preface tones-- tonus solemnis , tonus ferialis, and tonus solemnior.
www.newliturgicalmovement.org/2007_12_01_archive.html